docs: def check_platform_variables(self, ds):
          '''
          The value of platform attribute should be set to another variable which
          contains the details of the platform. There can be multiple platforms
          involved depending on if all the instances of the featureType in the
          collection share the same platform or not. If multiple platforms are
          involved, a variable should be defined for each platform and referenced
          from the geophysical variable in a space separated string.
  
          :param netCDF4.Dataset ds: An open netCDF dataset
          '''
          platform_names = getattr(ds, 'platform', '').split(' ')
          val = all(platform_name in ds.variables for platform_name in platform_names)
          msgs = []
          if not val:
              msgs = [('The value of "platform" global attribute should be set to another variable '
                       'which contains the details of the platform. If multiple platforms are '
                       'involved, a variable should be defined for each platform and referenced '
                       'from the geophysical variable in a space separated string.')]
          return [Result(BaseCheck.HIGH, val, 'platform variables', msgs)]